Water repellent size for fiber products



Patented Jan. 16, 1934 UNITED STATES PATENT OFFICE Elbert C. Lathrop andFergus A. 111., assignors to The Celotex Irvine, Chicago, Company,Chicago, Ill., a corporation of Delaware No Drawing. Application SerialNo.

8 Claims.

This invention relates to the treatment of fiber or fibrous materialswhereby the same is (water repellent), sized and given color, and hasfor its object to provide a method of treatment, as well as a finishedproduct, which can be economically carried out in a. manner moreefficient than those heretofore proposed.

In the use of numerous of the fibers which are utilized for themanufacture of paper, board, and insulating board, it is quite commonthat the color of the fibers may vary according to the season of thewarm because of some other more or less uncontrollable condition. In themanufacture of board and insulating boards, due particularly to the factthat insulating boards are largely manufactured of raw materialsseasonably obtained from vegetative sources, it is common for the colorto vary in accordance with the length of time that the basic fibrousmaterial thereof has been in storage. Further, in the manufacture ofboard and insulating board, the fibrous material generally is digestedonly lightly and ordinarily is not bleached, as a result of which thereis at times a considerable variation in the color of the resultingproduct.

It is a particular object of this invention to provide a treatment offibrous materials utilized in the production of paper, board, andinsulating board whereby a uniform color may be maintained in thefinished product and a further object of the invention is to provide afiber treatment which can be employed simultaneously to produce integralwater repellent sizing of the product and to maintain a uniform coloringthereof. Other and further objects of the invention will become apparentupon reading the following detailed description.

The invention comprises what might be termed a simultaneous dyeing andintegral sizing of the fibrous material which treatment is appliedordinarily to the fiber while in the condition of half stock, and in theutilization of this treatment the usual rosin and alum sizing treatmentmay be dispensed with although this is unnecessary. In the ordinaryrosin and alum sizing treatment there is ordinarilya considerable amountof difliculty involved in obtaining the requisite water repellentcharacteristic of sizing which difliculty is apparently due to therelative sensitiveness of the rosin and alum process of sizing.According to this invention the simultaneous coloring and sizing of thestock is accomplished in a manner quite similar to the usual rosin andalum process and in fact a rosin emulsion is used which is identicalwith that used in the previous process.

November 6, 1930 493,913

Instead of using alum to precipitate and coagulate the rosin on thefiber, as rosin sizing, an iron salt preferably FeCla is used althoughother iron salts may be utilized, particularly one embody both FeCl: andF62(SO4)'3 since it may 0 be economical at times to obtain the desirediron salts by chlorination of F62(SO4)3 which commonly does not convertall of the salt from the sulphate to the chloride with the result thatthe final product is more or less a mixture of the 'sev- 65 oral salts.

To the fibrous material digested washed and refined or treated in anyother desired manner, and in a condition of half stock, there is addedthe size, for example one per cent of rosin emulsion, which is theordinary paper sizing rosin emulsion formed by heating and agitating therosin with an alkali, the amount of rosin emulsion being expressed inper cent of solids in the emulsion relative to the dry weight of fiberto which it is added. For the best results, the rosin emulsion should bedistributed thoroughly and uniformly through the fiber mass to which itis added, after which there is added a solution preferably containingone per cent more or less of FeCla based on the dry weight of fiber.This solution, as intimated above, may be replaced by a solutioncomprising a combination of salts such as both FeCla and F'e2(SO-1) 3.

Upon addition of the size precipitant and coagulant to the fibercontaining the rosin emulsion, the sizing is deposited on the fiberproducing an integrally sized product which, after being dried, will beresistant to wetting. It may be that, when the FeCh is added, the stockis outside the range of acidity or alkalinity within which the sizingwill be deposited most satisfactorily on the fibers, which range isapproximately between the pH of 4.0 and 8.0, in which case an adjustmentmay be made with NaOH or other alkali to bring the pH within the mostsatisfactory range, which latter appears to be between pH 4.5 and pH5.5.

The action in this method of sizing is apparently due to the fact thatthe FeCl; reacts to form FeiOI-Da or basic ferric salts under theconditions 1 of and within the pH range of the treatment. The Fe(OH)3apparently acts on the rosin emulsion in the same general manner as doesalum with the result that apparently a resinate of iron is deposited inplace of the usual aluminum resinate.

It has been discovered that the amount of FeCla to be added, it inexcess of the minimum, may be increased to a quite considerable extent,

that is, to 3 or even 5 or more times the minimum amount necessary andthat, by adding the F'eClz in varying amounts between the minimumnecessary and that of several times the minimum, it is possible toproduce a fiber colored through a considerable range of the shades ofbrown. Further, by increasing and decreasing the amount of added F8C13,it has been found possible to compensate for variation in the color ofthe stock and, by such manipulation, to produce finished fiber productsof a substantially uniform shade of color.

A particular advantage of this process, not heretofore mentioned, isthat the action involved in precipitating and coagulating the size uponthe fibers is apparently not nearly so critical as is the case with alumsizing, and therefore by this process the sizing is greatly simplifiedand more uniform results can be obtained.

It is to be understood that if the fiber stock is dark or if arelatively light board is desired as the final product then in suchevent the rosin coagulating and precipitating agent may comprise amixture of alum and ferric chloride in which the proportions will varydepending upon the shade of color desired in the final product.

It is to be understood that the invention hereof is directed to a waterrepellent size application as distinguished from a water proofingtreatment.

A water proofing treatment is considered to be a treatment wherein theprotection is afforded through the use of a water impervious-materialapplied as a coating or used as a binder or matrix in which the fibrousmaterial is embedded and in which the proportion of water proofingmaterial with respect to fiber, for protection, is from about one partwaterproofing to four parts of fiber to equal proportions ofwaterproofing and fiber.

On the other hand a water resistant size is considered to be a treatmentof the usual rosin and alum sizing or a treatment of like effectachieved with other materials and wherein the results are apparently dueto a colloidal deposit of the water repellent substance on the fibersurfaces as distinguished from a water impervious coating or embedmentthereof and wherein the results are obtained by the use of size in theratio of about, size to 2 /2 parts to fiber 100 parts.

It is obvious that those skilled in the art may vary the steps andcombinations of steps constituting the method, as well as vary theingredients above mentioned, within the scope of this invention, andtherefore it is not desired to be limited to the foregoing disclosureexcept as may be required by the claims.

What is claimed is,-

1. The method of controlling the coloring of fiber products wherein, inintegrally sizing fibers to cause the products made therefrom to bewater repellent, wherein as the size precipitant, ferric saltsconsisting principally of ferric chloride are added in varyingquantities depending upon the shade of coloring desired, from theminimum for sizing to ten per cent by weight of dry fibers treated.

2. The method of coloring and sizing for making fiber products waterrepellent, consisting in adding to fibers in dilute suspension anemulsion of a sizing agent, the sizing agent coagulated and precipitatedon the fiber by addition of a coagulating and precipitating agentcomprising principally ferric chloride.

3. The method of sizing fiber materials by the coagulation andprecipitation of rosin with ferric chloride.

4. The method of precipitating and coagulating rosin size, whichconsists in bringing into contact therewith, while in dilute suspensiontogether with fiber, an iron salt comprising principally ferricchloride.-

5. A method of sizing a paper pulp derived from vegetative sources whichconsists in treating the pulp while in dilute suspension of 0.5 per centto 5.0 per cent consistency with 1.0 per cent to 3.0 per cent of anemulsion of an integral waterproofing sizing agent, and with 0.25 to 2.5per cent of ferric salt comprising principally ferric chloride.

6. Fiber products sized with the reaction product of rosin and ferricchloride.

7. Fiber products integrally sized to be water repellent with rosincoagulated and precipitated by a coagulant and precipitant comprisingprincipally ferric chloride and alum.

8. The method of sizing fiber materials wherein rosin is coagulated andprecipitated on the fiber by the use of a coagulant and precipitantconsisting of principally ferric chloride and alum.

ELBERT C. LATHROP. FERGUS A. IRVINE.

